I just recently purchased this game. It came in a dual disk jewel case, and had an extra disk included. This extra disk is considerally smaller, like the size of a gamecube disk. I am wondering, what is this for? I havnt actually tried it out yet, but figured I'd ask here in case anyone else may have this game.

Nah, never heard of a game coming with one. After I posted in the forum, I went ahead and tried it in my PC. Like ya said, just audio stuff. I have seen other programs come with smaller disks like this, just not the Turbo.